From e1a85f898e0781c9dd69ced6cd6ccb4e304a7bd1 Mon Sep 17 00:00:00 2001
From: jussi
Date: Fri, 9 Dec 2022 16:02:28 +0200
Subject: Draw Mesh Instanced Example.

---
 API.md                                             |  12 ++-
 changelog                                          |   2 +
 examples/bunnymark/main.lua                        |  11 +-
 examples/instancing/main.lua                       | 112 +++++++++++++++++++++
 examples/resources/lib/gui.lua                     |   2 +-
 examples/resources/shaders/glsl330/lighting.fs     |  82 +++++++++++++++
 .../shaders/glsl330/lighting_instancing.vs         |  36 +++++++
 include/models.h                                   |   1 +
 src/lua_core.c                                     |   1 +
 src/models.c                                       |  37 ++++++-
 src/rmath.c                                        |   2 +-
 11 files changed, 282 insertions(+), 16 deletions(-)
 create mode 100644 examples/instancing/main.lua
 create mode 100644 examples/resources/shaders/glsl330/lighting.fs
 create mode 100644 examples/resources/shaders/glsl330/lighting_instancing.vs

diff --git a/API.md b/API.md
index e625af1..f5d1473 100644
--- a/API.md
+++ b/API.md
@@ -4070,7 +4070,6 @@ Draw a 3d mesh with material and transform
 > success = RL_DrawMeshInstanced( Mesh mesh, Material material, Matrix{} transforms, int instances )
 
 Draw multiple mesh instances with material and different transforms
-Note! Untested.
 
 - Failure return false
 - Success return true
@@ -4171,6 +4170,15 @@ Set value for a material map type
 
 ---
 
+> success = RL_SetMaterialShader( Material material, Shader shader )
+
+Set shader for material
+
+- Failure return false
+- Success return true
+
+---
+
 ## Models - Model
 
 ---
@@ -5363,7 +5371,7 @@ Invert provided matrix
 
 ---
 
-> result = MatrixIdentity()
+> result = RL_MatrixIdentity()
 
 Get identity matrix
 
diff --git a/changelog b/changelog
index e630e73..2877f0f 100644
--- a/changelog
+++ b/changelog
@@ -10,6 +10,7 @@ KEY CHANGES:
 	- ADDED: Flag option (-s) for doc_parser.lua for exporting module APIs to separate files.
 	- ADDED: ReiLuaGui.
 	- ADDED: ReiLuaGui Examples.
+	- ADDED: Draw Mesh Instanced Example.
 
 Detailed changes:
 ADDED: Help argument.
@@ -21,3 +22,4 @@ FIXED: RL_DrawLineBezierQuad was called RL_DrawLineBezier in API.
 ADDED: Color lib.
 FIXED: RL_DrawEllipse and RL_DrawEllipseLines expecting wrong arguments.
 ADDED: RL_IsPathFile.
+ADDED: RL_SetMaterialShader.
diff --git a/examples/bunnymark/main.lua b/examples/bunnymark/main.lua
index 8672887..8bdc9b9 100644
--- a/examples/bunnymark/main.lua
+++ b/examples/bunnymark/main.lua
@@ -1,3 +1,6 @@
+-- Forked from raylib-lua example by TSnake41
+-- https://github.com/TSnake41/raylib-lua/blob/master/examples/textures_bunnymark.lua
+
 local MAX_BUNNIES = 100000
 
 -- This is the maximum amount of elements (quads) per batch
@@ -39,8 +42,6 @@ function Bunny:update()
 	end
 end
 
--- Init
-
 function init()
 	RL_SetWindowState( FLAG_VSYNC_HINT )
 	RL_SetWindowSize( { screenWidth, screenHeight } )
@@ -50,8 +51,6 @@ function init()
 	texSize = RL_GetTextureSize( texBunny )
 end
 
--- Update
-
 function process( delta )
 	if RL_IsMouseButtonDown( 0 ) then
 	 	-- Create more bunnies
@@ -59,7 +58,7 @@ function process( delta )
 			if #bunnies < MAX_BUNNIES then
 				local speed = { math.random( -250, 250 ) / 60, math.random( -250, 250 ) / 60 }
 				local color = { math.random( 50, 240 ), math.random( 80, 240 ), math.random( 100, 240 ), 255 }
-				table.insert( bunnies, Bunny:new( RL_GetMousePosition(), speed, color) )
+				table.insert( bunnies, Bunny:new( RL_GetMousePosition(), speed, color ) )
 			end
 		end
 	end
@@ -69,8 +68,6 @@ function process( delta )
 	end
 end
 
-  -- Draw
-
 function draw()
 	RL_ClearBackground( RAYWHITE )
 
diff --git a/examples/instancing/main.lua b/examples/instancing/main.lua
new file mode 100644
index 0000000..bcd9575
--- /dev/null
+++ b/examples/instancing/main.lua
@@ -0,0 +1,112 @@
+--[[
+	This example is translated from "raylib [shaders] example - Mesh instancing"
+	-- https://github.com/raysan5/raylib/blob/master/examples/shaders/shaders_mesh_instancing.c
+
+	Contributed by @seanpringle
+	Reviewed by Max (@moliad) and Ramon Santamaria (@raysan5)
+
+	Modified by Jussi Viitala (@nullstare) for ReiLua style.
+]]
+
+local MAX_INSTANCES = 10000
+
+local cube
+local transforms = {}
+local camera
+
+local shader
+local matInstances
+local matDefault
+
+function init()
+	local monitor = 0
+	local mPos = RL_GetMonitorPosition( monitor )
+	local mSize = RL_GetMonitorSize( monitor )
+	local winSize = RL_GetWindowSize()
+	-- local winSize = { 1920, 1080 }
+
+	RL_SetWindowState( FLAG_WINDOW_RESIZABLE )
+	RL_SetWindowSize( winSize )
+	RL_SetWindowPosition( { mPos[1] + mSize[1] / 2 - winSize[1] / 2, mPos[2] + mSize[2] / 2 - winSize[2] / 2 } )
+	RL_SetWindowTitle( "Instancing" )
+	RL_SetWindowState( FLAG_VSYNC_HINT )
+
+	-- Define the camera to look into our 3d world
+	camera = RL_CreateCamera3D()
+	RL_SetCamera3DPosition( camera, { -125.0, 125.0, -125.0 } )
+	RL_SetCamera3DTarget( camera, { 0, 0, 0 } )
+	RL_SetCamera3DUp( camera, { 0, 1, 0 } )
+	RL_SetCamera3DFovy( camera, 45 )
+	RL_SetCameraMode( camera, CAMERA_ORBITAL )
+
+	-- Define mesh to be instanced
+	cube = RL_GenMeshCube( { 1, 1, 1 } )
+
+	-- Translate and rotate cubes randomly
+	for i = 1, MAX_INSTANCES do
+		local translation = RL_MatrixTranslate( { math.random( -50, 50 ), math.random( -50, 50 ), math.random( -50, 50 ) } )
+		local axis = RL_Vector3Normalize( { math.random( 0, 360 ), math.random( 0, 360 ), math.random( 0, 360 ) } )
+		local angle = math.rad( math.random( 0, 10 ) )
+		local rotation = RL_MatrixRotate( axis, angle )
+
+		table.insert( transforms, RL_MatrixMultiply( rotation, translation ) )
+	end
+
+	-- Load lighting shader
+	shader = RL_LoadShader( RL_GetBasePath().."../resources/shaders/glsl330/lighting_instancing.vs",
+							RL_GetBasePath().."../resources/shaders/glsl330/lighting.fs" )
+
+	-- Get shader locations
+	local mvpLoc = RL_GetShaderLocation( shader, "mvp" )
+	local viewPosLoc = RL_GetShaderLocation( shader, "viewPos" )
+	local instanceTransformLoc = RL_GetShaderLocationAttrib( shader, "instanceTransform" )
+	RL_SetShaderLocationIndex( shader, SHADER_LOC_MATRIX_MVP, mvpLoc )
+	RL_SetShaderLocationIndex( shader, SHADER_LOC_VECTOR_VIEW, viewPosLoc )
+	RL_SetShaderLocationIndex( shader, SHADER_LOC_MATRIX_MODEL, instanceTransformLoc )
+
+	-- Set shader value: ambient light level
+	local ambientLoc = RL_GetShaderLocation( shader, "ambient" )
+	RL_SetShaderValue( shader, ambientLoc, { 0.2, 0.2, 0.2, 0.1 }, SHADER_UNIFORM_VEC4 )
+
+	-- Create one light
+	RL_CreateLight( LIGHT_DIRECTIONAL, { 50.0, 50.0, 0.0 }, RL_Vector3Zero(), WHITE, shader )
+
+	-- NOTE: We are assigning the intancing shader to material.shader
+    -- to be used on mesh drawing with DrawMeshInstanced()
+	matInstances = RL_LoadMaterialDefault()
+	RL_SetMaterialShader( matInstances, shader )
+	RL_SetMaterialColor( matInstances, MATERIAL_MAP_DIFFUSE, RED )
+
+	-- Load default material (using raylib intenral default shader) for non-instanced mesh drawing
+    -- WARNING: Default shader enables vertex color attribute BUT GenMeshCube() does not generate vertex colors, so,
+    -- when drawing the color attribute is disabled and a default color value is provided as input for thevertex attribute
+	matDefault = RL_LoadMaterialDefault()
+	RL_SetMaterialColor( matDefault, MATERIAL_MAP_DIFFUSE, BLUE )
+end
+
+function process( delta )
+	RL_UpdateCamera3D( camera )
+
+	-- Update the light shader with the camera view position
+	local loc = RL_GetShaderLocationIndex( shader, SHADER_LOC_VECTOR_VIEW )
+	RL_SetShaderValue( shader, loc, RL_GetCamera3DPosition( camera ), SHADER_UNIFORM_VEC3 )
+end
+
+function draw()
+	RL_ClearBackground( DARKBLUE )
+
+	RL_BeginMode3D( camera )
+		-- Draw cube mesh with default material (BLUE)
+		RL_DrawMesh( cube, matDefault, RL_MatrixTranslate( { -10.0, 0.0, 0.0 } ) )
+
+		-- Draw meshes instanced using material containing instancing shader (RED + lighting),
+		-- transforms[] for the instances should be provided, they are dynamically
+		-- updated in GPU every frame, so we can animate the different mesh instances
+		RL_DrawMeshInstanced( cube, matInstances, transforms, MAX_INSTANCES )
+
+		-- Draw cube mesh with default material (BLUE)
+		RL_DrawMesh( cube, matDefault, RL_MatrixTranslate( { 10.0, 0.0, 0.0 } ) )
+	RL_EndMode3D()
+
+	RL_DrawFPS( { 10, 10 } )
+end
diff --git a/examples/resources/lib/gui.lua b/examples/resources/lib/gui.lua
index 4e4ee7e..da46744 100644
--- a/examples/resources/lib/gui.lua
+++ b/examples/resources/lib/gui.lua
@@ -45,7 +45,7 @@ Gui = {
 	padding = 2,
 	spacing = 4,
 	scrollbarWidth = 8,
-	scrollAmount = 10,
+	scrollAmount = 20,
 
 	heldCallback = nil,
 
diff --git a/examples/resources/shaders/glsl330/lighting.fs b/examples/resources/shaders/glsl330/lighting.fs
new file mode 100644
index 0000000..58845c8
--- /dev/null
+++ b/examples/resources/shaders/glsl330/lighting.fs
@@ -0,0 +1,82 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec3 fragPosition;
+in vec2 fragTexCoord;
+//in vec4 fragColor;
+in vec3 fragNormal;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+// Output fragment color
+out vec4 finalColor;
+
+// NOTE: Add here your custom variables
+
+#define     MAX_LIGHTS              4
+#define     LIGHT_DIRECTIONAL       0
+#define     LIGHT_POINT             1
+
+struct MaterialProperty {
+    vec3 color;
+    int useSampler;
+    sampler2D sampler;
+};
+
+struct Light {
+    int enabled;
+    int type;
+    vec3 position;
+    vec3 target;
+    vec4 color;
+};
+
+// Input lighting values
+uniform Light lights[MAX_LIGHTS];
+uniform vec4 ambient;
+uniform vec3 viewPos;
+
+void main()
+{
+    // Texel color fetching from texture sampler
+    vec4 texelColor = texture(texture0, fragTexCoord);
+    vec3 lightDot = vec3(0.0);
+    vec3 normal = normalize(fragNormal);
+    vec3 viewD = normalize(viewPos - fragPosition);
+    vec3 specular = vec3(0.0);
+
+    // NOTE: Implement here your fragment shader code
+
+    for (int i = 0; i < MAX_LIGHTS; i++)
+    {
+        if (lights[i].enabled == 1)
+        {
+            vec3 light = vec3(0.0);
+
+            if (lights[i].type == LIGHT_DIRECTIONAL)
+            {
+                light = -normalize(lights[i].target - lights[i].position);
+            }
+
+            if (lights[i].type == LIGHT_POINT)
+            {
+                light = normalize(lights[i].position - fragPosition);
+            }
+
+            float NdotL = max(dot(normal, light), 0.0);
+            lightDot += lights[i].color.rgb*NdotL;
+
+            float specCo = 0.0;
+            if (NdotL > 0.0) specCo = pow(max(0.0, dot(viewD, reflect(-(light), normal))), 16.0); // 16 refers to shine
+            specular += specCo;
+        }
+    }
+
+    finalColor = (texelColor*((colDiffuse + vec4(specular, 1.0))*vec4(lightDot, 1.0)));
+    finalColor += texelColor*(ambient/10.0)*colDiffuse;
+
+    // Gamma correction
+    finalColor = pow(finalColor, vec4(1.0/2.2));
+}
diff --git a/examples/resources/shaders/glsl330/lighting_instancing.vs b/examples/resources/shaders/glsl330/lighting_instancing.vs
new file mode 100644
index 0000000..6775a2e
--- /dev/null
+++ b/examples/resources/shaders/glsl330/lighting_instancing.vs
@@ -0,0 +1,36 @@
+#version 330
+
+// Input vertex attributes
+in vec3 vertexPosition;
+in vec2 vertexTexCoord;
+in vec3 vertexNormal;
+//in vec4 vertexColor;      // Not required
+
+in mat4 instanceTransform;
+
+// Input uniform values
+uniform mat4 mvp;
+uniform mat4 matNormal;
+
+// Output vertex attributes (to fragment shader)
+out vec3 fragPosition;
+out vec2 fragTexCoord;
+out vec4 fragColor;
+out vec3 fragNormal;
+
+// NOTE: Add here your custom variables
+
+void main()
+{
+    // Compute MVP for current instance
+    mat4 mvpi = mvp*instanceTransform;
+
+    // Send vertex attributes to fragment shader
+    fragPosition = vec3(mvpi*vec4(vertexPosition, 1.0));
+    fragTexCoord = vertexTexCoord;
+    //fragColor = vertexColor;
+    fragNormal = normalize(vec3(matNormal*vec4(vertexNormal, 1.0)));
+
+    // Calculate final vertex position
+    gl_Position = mvpi*vec4(vertexPosition, 1.0);
+}
diff --git a/include/models.h b/include/models.h
index 0113b62..606e003 100644
--- a/include/models.h
+++ b/include/models.h
@@ -45,6 +45,7 @@ int lmodelsUnloadMaterial( lua_State *L );
 int lmodelsSetMaterialTexture( lua_State *L );
 int lmodelsSetMaterialColor( lua_State *L );
 int lmodelsSetMaterialValue( lua_State *L );
+int lmodelsSetMaterialShader( lua_State *L );
 /* Model. */
 int lmodelsLoadModel( lua_State *L );
 int lmodelsLoadModelFromMesh( lua_State *L );
diff --git a/src/lua_core.c b/src/lua_core.c
index 2a07a90..acf4843 100644
--- a/src/lua_core.c
+++ b/src/lua_core.c
@@ -1028,6 +1028,7 @@ void luaRegister() {
 	lua_register( L, "RL_SetMaterialTexture", lmodelsSetMaterialTexture );
 	lua_register( L, "RL_SetMaterialColor", lmodelsSetMaterialColor );
 	lua_register( L, "RL_SetMaterialValue", lmodelsSetMaterialValue );
+	lua_register( L, "RL_SetMaterialShader", lmodelsSetMaterialShader );
 		/* Model. */
 	lua_register( L, "RL_LoadModel", lmodelsLoadModel );
 	lua_register( L, "RL_LoadModelFromMesh", lmodelsLoadModelFromMesh );
diff --git a/src/models.c b/src/models.c
index bc84f6c..f2f7f2e 100644
--- a/src/models.c
+++ b/src/models.c
@@ -1287,12 +1287,10 @@ int lmodelsDrawMesh( lua_State *L ) {
 	return 1;
 }
 
-/* TODO Untested. */
 /*
 > success = RL_DrawMeshInstanced( Mesh mesh, Material material, Matrix{} transforms, int instances )
 
 Draw multiple mesh instances with material and different transforms
-Note! Untested.
 
 - Failure return false
 - Success return true
@@ -1305,14 +1303,14 @@ int lmodelsDrawMeshInstanced( lua_State *L ) {
 	}
 	int instances = lua_tointeger( L, -1 );
 	lua_pop( L, 1 );
-	Matrix matrises[ instances ];
+	Matrix transforms[ instances ];
 
 	int t = lua_gettop( L ), i = 0;
     lua_pushnil( L );
 
 	while ( lua_next( L, t ) != 0 ) {
         if ( lua_istable( L, -1 ) ) {
-			matrises[i] = uluaGetMatrix( L );
+			transforms[i] = uluaGetMatrix( L );
         }
         i++;
         lua_pop( L, 1 );
@@ -1326,7 +1324,7 @@ int lmodelsDrawMeshInstanced( lua_State *L ) {
 		lua_pushboolean( L, false );
 		return 1;
 	}
-	DrawMeshInstanced( *state->meshes[ meshId ], *state->materials[ materialId ], matrises, instances );
+	DrawMeshInstanced( *state->meshes[ meshId ], *state->materials[ materialId ], transforms, instances );
 	lua_pushboolean( L, true );
 
 	return 1;
@@ -1699,6 +1697,35 @@ int lmodelsSetMaterialValue( lua_State *L ) {
 	return 1;
 }
 
+/*
+> success = RL_SetMaterialShader( Material material, Shader shader )
+
+Set shader for material
+
+- Failure return false
+- Success return true
+*/
+int lmodelsSetMaterialShader( lua_State *L ) {
+	if ( !lua_isnumber( L, -2 ) || !lua_isnumber( L, -1 ) ) {
+		TraceLog( LOG_WARNING, "%s", "Bad call of function. RL_SetMaterialShader( Material material, Shader shader )" );
+		lua_pushboolean( L, false );
+		return 1;
+	}
+	size_t shaderId = lua_tointeger( L, -1 );
+	lua_pop( L, 1 );
+	size_t materialId = lua_tointeger( L, -1 );
+
+	if ( !validMaterial( materialId || !validShader( shaderId ) ) ) {
+		lua_pushboolean( L, false );
+		return 1;
+	}
+
+	state->materials[ materialId ]->shader = *state->shaders[ shaderId ];
+	lua_pushboolean( L, true );
+
+	return 1;
+}
+
 /*
 ## Models - Model
 */
diff --git a/src/rmath.c b/src/rmath.c
index 141f8d5..a83eac4 100644
--- a/src/rmath.c
+++ b/src/rmath.c
@@ -1607,7 +1607,7 @@ int lmathMatrixInvert( lua_State *L ) {
 }
 
 /*
-> result = MatrixIdentity()
+> result = RL_MatrixIdentity()
 
 Get identity matrix
 
-- 
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